Glass breaking tools are known and widely used for breaking glass, in particular for breaking a glass pane in case of emergency. It can for example be used for breaking a car window or window of a train or tram by a passenger to escape the vehicle in case of emergency. Also, it can be used by a rescue helper for breaking a window of a vehicle rescue victims from the vehicle.
Various glass breaking tools are available. Glass breaking tools such as hammers are known in which the user actively has to break the glass. Also, pretensioned glass breaking tools are known. A pretensioned glass breaking tool is placed by a user against the glass to be broken. The user activates a glass breaking pin crusher by operating a button or a knob or a handle or a housing or any other activating means.
Publication U.S. Pat. No. 6,418,628 describes a spring-loaded glass breaking tool that is adjustable between a ready position, a cocked position, a fire position and a break position. The tool comprises a housing that is slidable over a safety sheath enclosing the pin crusher. An end of the safety sheath is placed against the glass pane. By sliding the housing over the safety sheath, the tool is activated. The pin crusher has in rest a position that is oblique with respect to the longitudinal axis of the tool and has to be aligned before it can move to the break position. In the cocked position, the housing is moved over the safety sheath and the pin crusher is oblique. In the fire position, the pin crusher is aligned by a sleeve ramp of a sleeve arranged inside the safety sheath. When the pin crusher is aligned, it can be pushed to the break position by spring action.
A drawback of this tool is that it may not be reliably since the pin crusher may not be launched when required when the alignment does not occur. Also, the tool may not be safe to use since the pin crusher may be launched unintentionally. Further, due to the four-position adjustment, the tool is rather complex. In addition, it may be difficult to reset the tool from the break position to the ready position to allow multiple uses.
Publication U.S. Pat. No. 5,791,056 describes a spring-loaded glass breaking tool in which the pin crusher is activated by a knob. The knob is movable into the housing and is pretensioned by a spring towards a ready position. By pressing the knob against the spring tension, the tip of the pin crusher is moved outside the housing. Suction caps are placed on the end of the housing that is put against the glass pane.
A drawback of this tool is that it is relatively difficult to operate. A user has to apply a relatively large force on the knob against the spring tension to move the pin crusher such that it breaks the glass. Also, by using suction cups the tool may not be optimally positioned against the glass pane to provide an optimal position for the pin crusher to break the glass.
Publication GB 2 356 212 discloses a glass breaking device, having a spring-loaded, sliding, pointed rod within a housing. In a hand held embodiment, the device would be operated by pressing an end of the device against the glass and applying pressure to a handle of the device, thereby releasing a mechanism rod. In this case, a compressed spring is located just behind the sliding bar, in the distal end of the device, remote from the handle. The handle includes a second spring. The resulting device is relatively bulky (particularly relatively large in a longitudinal direction) and complex.